What's New in PHP4?

What's New in PHP4? PHP4 introduces numerous new features that will make the programmer's life more

interesting. Let's take a quick look at some of them.

A new foreach statement, similar to that found in Perl, makes it much easier to

loop through arrays. We will be using this for most of the array examples in this

book. Additionally, a raft of new array functions have been added, making arrays

easier to manipulate.

The language now includes the boolean data type.

A particularly useful feature of PHP3 was the capability to name form elements

as if they were elements in an array. The elements' names and values are then

made available to the code in array form. This feature has been extended to

support multidimensional arrays.

Support for object-oriented programming was somewhat rudimentary in PHP.

This is significantly extended in PHP4; for example, it is now possible to call an

overridden method from a child class.

PHP4 now provides native support for user sessions, using both cookies and the

query string. You can now "register" a variable with a session, and then access

the same variable name and value in subsequent user requests.

A new comparison operator (===) has been introduced that tests for

equivalence of type as well as equivalence of value.

New associative arrays containing server and environmental variables have

been made available, as well as a variable that holds information about uploaded

files.

PHP4 now provides built-in support for both Java and XML.

Although these and other features significantly improve the language, perhaps the

most significant change has taken place under the hood